Communication in River Otters: Creation of Variable Resource Sheds for Terrestrial Communities

Abstract

Movements and behavior of animals can result in transfer of nutrients between discrete spatial patches, leading to spatial and temporal variability in resource sheds, modification of nutrient cycling, changes in productivity and in community structure and function, and increases in landscape heterogeneity. In this study, we explored the function of scent-marking at latrines by coastal river otters (Lontra canadensis), through investigating spatial distributions of otters with respect to gender, sociality, and the distribution of their food resources. We then calculated the amounts of nitrogen (N) and phosphorus (P) transported to latrine sites based on otter foraging behavior and the function of scent-marking at latrines. Locations of 55 radio-tagged otters in Prince William Sound, Alaska, USA, were obtained through aerial telemetry over a period of four years. Data on fish densities and marine habitat features were concurrently obtained from scuba transects and aerial surveys. A plastic social organization in river otters resulted in different foraging strategies and scent-marking behaviors. Social otters were more closely associated with schooling fishes and used latrines for intra-group communication, whereas nonsocial otters, which concentrated on intertidal and subtidal fishes, probably signaled mutual avoidance. In contrast, females appeared to use latrines for the defense of territories. Social otters used fewer sites with greater intensity, whereas nonsocial otters used more sites with lower intensity. These different functions of scent-marking and associated behaviors of otters resulted in high variability in nutrient inputs to different latrine sites. Although some sites may receive 2.7 g N·m Ϫ2 ·yr Ϫ1 and 0.4 g P·m Ϫ2 ·yr Ϫ1 , others may be fertilized with up to 47.6 g N·m Ϫ2 ·yr Ϫ1 and 6.7 g P·m Ϫ2 ·yr Ϫ1 . This spatial variability and the temporal changes in resource sheds is likely to result in the creation of heterogeneous landscape at the land margin.

Classification of Captive North American River Otters (Lontra canadensis) Vocal Repertoires: Individual Variations, and Age Class Comparisons

“…Because the degree of sociality varies between and within habitat types, it is likely that communication in river otters is also flexible and serves several functions (Rostain, Ben-David, Groves, & Randall, 2004). Research shows Prince William Sound nonsocial otters deposit spraints at more latrines sites than social otters, and this serves to facilitate mutual avoidance (Ben-David, Blundell, Kern, Brown, & Jewitt, 2005). As well, documented observations suggest that during social interactions vocalizations are flexible.…”

Indirect effects of bioinvasions in Yellowstone Lake: The response of river otters to declines in native cutthroat trout

“…Less often has this debate addressed the consequences of mitigating biological invasions in one ecosystem on linked ecological processes in an adjacent one. For example, river otters transfer aquatically-derived nutrients to terrestrial habitats via their scent-marking behavior at latrines and create "hot spots" of nutrient heterogeneity at the waterland interface (Ben-David et al, 2005;Crait and Ben-David, 2007;Roe et al, 2010). Our finding of behavioral changes in latrine use suggests that the spatial distribution of these hot spots may have shifted away from tributary streams.…”

“…This covariate likely explained individual heterogeneity in p associated with the observation process, and therefore reduced potential bias in parameter estimates (Pollock et al, 1990). Finally, we allowed p to differ for male and female otters based on possible sex-specific differences in intensity of latrine site use and aversion to hair snares (Ben-David et al, 2005). Including models with additive effects resulted in the following seven parameterizations for p: p(sex), p(effort), p(access), p(effort + access), p(sex + effort), p(sex + access), and p(sex + effort + access).…”

Summer Diet Characteristics of North American River Otters (Lontra canadensis) in Central Illinois

“…These sites are an integral component of river otter communication and social interactions where social status may be communicated across individuals (Rostain et al, 2004;Ben-David et al, 2005;Oldham and Black, 2009). These sites may be 5-20 m in radius with as many as 160 latrines possible along 100 km of shoreline (Ben-David et al, 1998).…”